Dry disconnect systems to fuel fleet vehicles, such as for example busses, are known. The fuel systems allow for rapid fueling of buses with minimal leakage of fuel into the environment. One type of dry disconnect system includes a coupling which couples with an adaptor of a fuel tank. In more detail, the coupling is connected to one end of a hose. The other end of the hose is connected to a fuel pump. In use, the coupling, which can be a nozzle, is coupled to the adaptor. Fuel is dispensed from the pump into and through the hose. The fuel passes into and through the coupler. From the coupler the fuel passes into the adaptor. From the adaptor the fuel passes into the fuel tank. The coupler is mechanically coupled and locked to the adapter.
When the adapter is locked onto the coupler, poppet valves of both the coupler and adaptor are displaced by an operator from their seats to permit flow of fluid through the coupler and into the adaptor. When the tank reaches a full level, an overpressure shut-off assembly causes a main valve in the coupler to close and prevents further dispensing of fuel from the coupler. Upon uncoupling of the coupler from the adaptor, the poppet valves are oriented back on the valve seats, sealing off the adaptor opening and the coupler opening. The sealing prevents leakage of the fuel from the coupler and adaptor into the environment.
Vacuum shutoffs are also known. A vacuum shutoff system automatically shuts off the flow of fluid to the fuel tank once the fuel tank is full. U.S. Pat. No. 5,755,256 concerns an automatic shut off filling system. The system includes a nozzle body component associated with a fluid supply and a nozzle extension component for mounting within a container to be filled. The nozzle body component includes a fluid filling nozzle having automatic shut off means actuated in response to changes in pressure within the nozzle body caused by the fluid when it reaches a fill level within the container to be filled. The nozzle body also has a fluid delivery actuation means associated with it. The fluid filling nozzle further includes quick disconnect coupling means for securing the nozzle body component to the fill neck of the container to be filled. A shutoff tube is mounted within a fluid delivery passage located within the coupling means. The shutoff tube is adapted to removably engage an end of a shutoff tube extension associated with the nozzle extension component.